Development and internal validation of a multivariable prediction model for biochemical failure after focal salvage high intensity focused ultrasound for locally recurrent prostate cancer: presentation of a risk score for individual patient prognosis.
BAUS ePoster online library. Peters M. 06/30/16; 132007; P10-7
Dr. Max Peters
Dr. Max Peters
Login now to access Regular content available to all registered users.

You may also access this content "anytime, anywhere" with the Free MULTILEARNING App for iOS and Android
Abstract
Discussion Forum (0)
Rate & Comment (0)
P10-7

Introduction: Locally recurrent prostate cancer after primary radiotherapy might be curatively treated using focal salvage. Optimal patient selection is essential. This study therefore aims to develop a prediction model for biochemical failure (BF) following focal salvage high intensity focused ultrasound (HIFU).

Materials and methods: A comprehensive registry was used (Nov 2006-Sept 2014). Recurrences were assessed with multi-parametric MRI combined with template prostate mapping biopsies or systematic TRUS-guided biopsies as well as PET/CT and a bone-scan. Quadrant or hemi-ablation was applied. With Cox proportional-hazards regression, the effect of determinants on BF (Phoenix-definition) was assessed. Multiple imputation was used for missing data. Internal validation was performed using bootstrap resampling (500 datasets). Calibration plots and the C-statistic were adopted to assess model performance. Finally, a risk score was created.

Results: 139 patients were identified. Primary treatment consisted of external beam radiotherapy (EBRT, n=134) or EBRT with high dose rate brachytherapy (n=5). Mean follow-up was 37 months (sd 21 months). BF occurred in 71, resulting in 50% biochemical disease-free survival (bDFS) at 35 months. Multivariable, disease-free survival interval (DFSI) after primary radiotherapy, pre-salvage PSA, PSA doubling time (PSADT), prostatic volume and T-stage (both MRI-based) were independent predictors (Table 1). The adjusted C-statistic was 0.69. Calibration was accurate up to 36 months. Our risk score consisted of 4 groups, highly predictive of bDFS at 3 years (88% [95%CI: 75-100%], 68% [51-81%], 33% [18-48%] and 20% [0-40%].

Conclusion: Improved focal salvage patient selection can increase recurrence free rates from 50% to almost 90% at 3 years.

 

 

P10-7

Introduction: Locally recurrent prostate cancer after primary radiotherapy might be curatively treated using focal salvage. Optimal patient selection is essential. This study therefore aims to develop a prediction model for biochemical failure (BF) following focal salvage high intensity focused ultrasound (HIFU).

Materials and methods: A comprehensive registry was used (Nov 2006-Sept 2014). Recurrences were assessed with multi-parametric MRI combined with template prostate mapping biopsies or systematic TRUS-guided biopsies as well as PET/CT and a bone-scan. Quadrant or hemi-ablation was applied. With Cox proportional-hazards regression, the effect of determinants on BF (Phoenix-definition) was assessed. Multiple imputation was used for missing data. Internal validation was performed using bootstrap resampling (500 datasets). Calibration plots and the C-statistic were adopted to assess model performance. Finally, a risk score was created.

Results: 139 patients were identified. Primary treatment consisted of external beam radiotherapy (EBRT, n=134) or EBRT with high dose rate brachytherapy (n=5). Mean follow-up was 37 months (sd 21 months). BF occurred in 71, resulting in 50% biochemical disease-free survival (bDFS) at 35 months. Multivariable, disease-free survival interval (DFSI) after primary radiotherapy, pre-salvage PSA, PSA doubling time (PSADT), prostatic volume and T-stage (both MRI-based) were independent predictors (Table 1). The adjusted C-statistic was 0.69. Calibration was accurate up to 36 months. Our risk score consisted of 4 groups, highly predictive of bDFS at 3 years (88% [95%CI: 75-100%], 68% [51-81%], 33% [18-48%] and 20% [0-40%].

Conclusion: Improved focal salvage patient selection can increase recurrence free rates from 50% to almost 90% at 3 years.

 

 

Code of conduct/disclaimer available in General Terms & Conditions

By clicking “Accept Terms & all Cookies” or by continuing to browse, you agree to the storing of third-party cookies on your device to enhance your user experience and agree to the user terms and conditions of this learning management system (LMS).

Cookie Settings
Accept Terms & all Cookies